Fluorescent labeling reagent

A fluorescent labeling reagent of the present invention includes an inorganic fluorescent particle and a material (A) having a material (B) of biological origin adsorbed or bound thereto. The inorganic fluorescent particle is integrated with the material (A) so as to form the reagent of the present invention. The inorganic fluorescent particle used in the present invention is capable of emitting light with a wavelength of 650 nm to 1600 nm in the infrared region or the near-infrared region which can be detected by means of Si—CCD or InGaAs—PD and can penetrate an H2O rich sample when excited by light with a wavelength of 650 nm or longer which has the shortest transparent wavelength of AlInGaP-LD including oxygen adsorption type hemoglobin used for DVDs etc.